Grammar on the GMAT

GMAT Verbal: which vs. that

At first glance, it’s difficult to identify a clear difference between the words “which” and “that.” However, both have unique characteristics that are important to understand, especially to master sentence correction questions. These two words are often misused in everyday conversion, requiring test-takers to take a step back and unlearn bad habits in preparation for the GMAT. Here’s how we recommend differentiating between these two common words in their most confusing usage: as relative pronouns that introduce relative clauses (also known as modifier clauses).

Quick review of concepts

A modifier clause provides additional information about a noun, either by clarifying defining characteristics of the unique instance of the noun in question (I was raised in a town that has a small population) or providing optional additional information about the noun in general (I was raised in a town, which is an urban area larger than a village and smaller than a city).

Notice how the underlined section in first example (I was raised in a town that has a small population) provides clarity as to the specific town that the narrator was raised in, while the underlined section in the second example (I was raised in a town, which is an urban area larger than a village and smaller than a city) isn’t helping you understand the specific town that the narrator was raised in, rather the phenomena of towns in general.

Did you notice how ‘that’ vs. ‘which’ were used?

When the information in the relative clause (anything underlined above) is essential to the meaning of the entire sentence, use “that.” On the other hand, when the information following a relative pronoun can be removed without changing the meaning of the sentence, use “which” and separate it using a comma.

Here’s another example:

1. John passes on beverages that are far too sugary.

2. John passes on beverages, which are far too sugary.

In the first sentence, which uses that as a modifier, the sentence indicates that John doesn’t drink beverages within one particular category. Since the modifier specifies the type of drink John does not enjoy, removing the modifier would change the entire meaning of the sentence. On the other hand, the second example does not exclude any type of beverages and is far less restricting in nature. It is also a far more scathing indictment of all beverages, which we know is extreme, but it is what the modifier in this case does to the second sentence.

But how do I choose?

As we previously mentioned, removing a restrictive modifier from a sentence can dramatically change the meaning (and often, by extension, the logic) of the entire sentence. On the other hand, the information following a non-restrictive modifier is far less significant to the overall meaning of a sentence and often serves as little more than background information. Take a look at the examples below and see if removing the underlined information would change the meaning of the sentence.

My entertainment system can’t support televisions (that/which) have wide screens.

The New York Marathon begins at the Verrazano Bridge, (that/which) connects the boroughs of Staten Island and Brooklyn.

In the first sentence, the entertainment system cannot support televisions that have wide screens. However, not all televisions have wide screens. If we were to select “which” as the modifier in this case, we would be indicating that all televisions have wide screens. Considering that televisions come in a variety of sizes, we would want to use “that” as our modifier in this instance. The second sentence, on the other hand, describes the only Verrazano Bridge in the world, making the information following the modifier inconsequential to the meaning of the sentence. In this case, “which” would be the correct modifier. You’ll also notice that in each example of a non-restrictive modifier, we set it off with a comma. This is also a telling indicator on the GMAT of which modifier is the correct choice.

Whew! Congratulations, you just read through an explanation of one of the most confusing GMAT Verbal topics out there. We hope it helped. And remember, if you find yourself getting stuck on that vs. which over and over again, be sure to use our Ask-a-Tutor function in the GMAT Tutor app so you can get the tutoring you need.

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